Conventionally, for example, a radiation picture recording apparatus for obtaining information about an affected-part or the like of a subject as effectively employed in the field of medical science or the like. In this example, a subject is subject to radiant rays and radiation image of the subject is image-wise formed on a silver halide monochromatic photographic material or the like. Next, the photographic material film on which the picture is recorded as described above is subjected to a developing step. That is, the image-wise exposed film is loaded into the automatic developing apparatus shown in FIG. 2.
First, the above mentioned film is sandwiched between a pair of rollers (4) and conveyed into a developing tank (1) containing a developer so that the film is developed. Next, the thus developed film is passed through a fixing tank (2) containing a fixer and then conveyed into a washing tank (3) containing washing water. After water attached on the film has been removed by squeezing the film between rollers or the like constituting a squeezing portion of the automatic developing apparatus as illustrated in FIG. 2, the film is conveyed to a drying portion at which hot air of a predetermined temperature (about 50.degree. C.-55.degree. C.) is blown onto the film to thereby dry it. Then, the film is stored in a predetermined area so as to be retrieved and utilized for medical diagnosis.
More particularly, in such an automatic developing apparatus as described above, there is provided a washing tank (3) for washing a film which has been passed through a developer and a fixer while it is immersed therein as described above. In this case, the washing tank is arranged such that a large quantity of washing water (for example, not less than 3 l per 1 m.sup.2 of the photographic material) is always fed into the washing tank (3) so as to keep the washing water in the washing tank (3) clean.
However, needless to say a supply of a large quantity of washing water is exceedingly uneconomical and that this supply is remarkably contrary to economization of natural resources which has been recently particularly desired. Further, there has been such a disadvantage that the large quantity of waste liquid from the washing water dilutes the silver concentration and decreases the efficiency of recovery of silver.
However, if the quantity of washing water to be supplied to the washing tank (3) is considerably decreased, the concentration of thiosulfate brought into the washing tank (3) by the film becomes high to reduce the degree of washing of the film, thereby decreasing the stability of a picture after processing. Also, a component of a processing agent becomes attached to and dried on the first rollers located outside the washing tank, and this dried processing component contaminates subsequent film to cause variations in density on the film. Further, when aluminum salt is contained in a fixer, the aluminum salt may deposit as a precipitate in the case where the quantity of washing water is insufficient. Further, if washing water is retained in the washing tank for a long time, a fur or the like is generated in the washing water or the washing water degrades to thereby generate a bad smell. If the automatic developing apparatus is stopped for a few days, suspended matter is generated in the washing water, and when the automatic developing apparatus is to be run again, the suspended matter may attach on a film, or a filter incorporated in the automatic developing apparatus may be clogged. Therefore, it is necessary to periodically cleanse the washing tank (3), so that there have been such disadvantages that a considerably long time is taken for the washing work and an excessive burden is imposed on the workers, and thus it is impossible to economize water in practice.
Conventionally, therefore, there have been proposed various automatic developing apparatus in order to effectively economize washing water to be supplied into the washing tank (3). For example, there has been proposed a counterflow washing system in which the washing tank (3) is comprised of a plurality of washing tanks. That is, arrangement is made such that the plurality of washing tanks are disposed so as to stepwise change the respective positions in height of the washing tanks to thereby supply a relatively small quantity of washing water from the uppermost washing tank (3) to other washing tanks located at lower positions, and a film is washed successively in the washing tanks while being sandwiched by each of a plurality of roller pairs (4) dipped in each of the washing tanks (3).
In the automatic developing apparatus of the kind as described above, however, there have been disadvantages in that it is necessary to arrange a plurality of washing tanks (3) and to provide at least a number of pairs of conveying rollers (4) corresponding to the number of the washing tanks (3). Accordingly, the whole automatic developing apparatus becomes large in size so that the space for the developing work cannot be effectively utilized and the manufacturing cost of this automatic developing apparatus becomes considerably high.
In view of the foregoing defects, there are proposed various developing and processing systems including one in which an anti-fungal agent, such as a chelating agent, a halogen group containing compound, or the like, is present in the washing water to thereby avoid rotting of the washing water and avoid generation of a fur or the like, thereby enabling to exceedingly decrease the quantity of washing water to be supplied into a washing tank (3), as shown in Japanese Unexamined Patent Application Publication Nos. 115154/1987 and 153952/1987 (not prior art). As a result, the effect obtained is the film washing work can be satisfactorily performed for a long time without making the automatic developing apparatus of the water stock type large in size and with the washing water economized as much as possible.
Unlike the first case described above where a sufficient quantity of washing water is supplied so as to wash a film, in this case where a film is washed by a small quantity of economized or retained water, as the quantity of developing increases, other defects are noticed, for example, thiosulfate from the fixer brought by a film being conveyed may be accumulated in the washing water in the washing tank. As a result, a silver image grows yellowish by the thiosulfate which remains on the film after the film has been preserved for a long time. Further, sometimes a washed film carrying the thiosulfate and the like is passed through a squeezing portion so as to be squeezed there, and the thiosulfate may attach on the roller pairs constituting this squeezing portion. Since the squeezing portion is disposed in the close vicinity of a film drying portion, when the film developing work is intermittently performed the roller pairs constituting the squeezing portion are quickly dried by hot air flowing from the film drying portion during a period of stoppage of the developing work. At this time, thiosulfate of high density is unevenly accumulated on the surfaces of the roller pairs, and when a washed film is conveyed by these roller pairs, the thiosulfate partially attaches onto the surface of the film, so that variations in density as well as in surface reflection are caused in a image portion on the film, or in that a portion of the film on which the thiosulfate attaches grows yellowish while the developed film is preserved for a long time.
In order to increase the recovery of silver in waste liquid from washing water and to easily remove thiosulfate during washing in a washing bath, it has been known to provide a tank for pre-washing bath in a stage preceding the washing bath. In the case where processing is performed by using this system, there are disadvantages in that when the density of a component brought by a silver halide photographic material (hereinafter, simply referred to as a photographic material) in the pre-washing bath reaches a certain value, the speed of elution of soluble silver salt from the photographic material in the pre-washing bath becomes slow, and in that the photographic material carries the solution of the silver salt into the washing bath and a large quantity of silver salt flows into washing water in the washing bath, so that the effect of the washing bath is considerably reduced.
As described above, usually almost all the fixer components are removed from the photographic material by the washing bath. In the case where only a small quantity of washing water is supplemented in the washing bath, there has been a serious problem in that the density of thiosulfate in the washing bath is increased, and when a film carrying the solution of the thiosulfate is squeezed by squeezing rollers the thiosulfate attaches to and is dried on the surfaces of the squeezing rollers. The dried thiosulfate is then transferred onto a subsequent film to thereby stain a surface of the film.
In the case where a photographic material contains a sensitizing dye and/or a dye (in order to screen irradiation, antihalation, or the like), there has been another serious disadvantage in that the speed of elution of the sensitizing dye and/or the dye is lower than that of elution of an inorganic salt group, so that a washing property of the photographic material is made poor and the washing by only the foregoing pre-washing bath and washing bath is insufficient for removing the sensitizing dye and/or the dye thus allowing the dye to remain in the photographic material.